Programmable high speed (~1MHz) Vernier-mode-locked frequency-swept laser for OCT imaging

We propose and demonstrate a programmable high-speed, frequency-swept laser for swept-source optical coherence tomography (SS-OCT). This new technique is based on Vernier effect of two pieces of Fabry-Perot electro-optic modulators. This technique offers a non-mechanical optical filter with high resolution and wide tuning range. By applying it to a Fourier domain mode-locked laser, such sweeps are generated. The Vernier effect filter can be modulated by arbitrary wave forms, thus this laser source can eliminate the rescaling process which is the main bottle-neck of the operation time in SS-OCT by applying frequency sweep to equidistant spacing in frequency. Effective repetition frequencies of 100kHz~1MHz are demonstrated with a tuning range of 17THz (140nm) at 1550nm center wavelength. OCT imaging of in vivo human sweat duct with A-line rate of 100kHz and 300kHz are also demonstrated. The resolution of 12μm~ is realized without rescaling process. We present an analysis which suggests design approaches for optimization performance.